One of the conditions necessary for ensuring high frequency signal transmission with minimum loss in the coaxial transmission lines, respectively coaxial cables and connectors, is to maintain a constant impedance over the entire length of the transmission line.
The impedance is directly linked to the transverse dimensions of the central conductor, the outer conductor and to the .epsilon. of the central dielectric. If the cables have a constant section over their entire length, this section is sometimes modified at the attachment location of the connector, especially if the outer conductor has to be deformed in order to ensure electric contact and the attachment of the cable. Modifying the dimensions of the cable causes an impedance fault which must be compensated in the connector. This compensation can be regulated. It is therefore only valid for a very precise impedance fault value, which is difficult to carry out during the assembly of the connector on the cable.
The connector for coaxial cables according to the present invention enables the cable to be attached by deforming the outer conductor (which ensures electric contact and the attachment of the connector) in an automatically reproducible manner without requiring precise measurements or subjective estimations during assembly, nor special tools.
The general principle of such a connector is known from the German patent 42 07 482 which specifies a method for connecting coaxial cables provided with an annularly corrugated outer conductor (ringforming gewellter Mantelrohr). The cable is cut at a corrugation trough and a piece destined to hold the cable is placed in the trough of the following corrugation. During the connecting operation of a front body and a rear body of the connector the corrugation left free by the holding piece is crushed in a relatively reproducible manner between the front body and the holding piece. This type of known connector nevertheless has the inconvenience that it does not prevent the rotation of the cable in the holding piece during the connecting operation, which can detract from the good reproducibility of the deformation of the outer conductor. Furthermore this type of connector is entirely specific to coaxial cables provided with an annularly corrugated outer conductor. It is therefore not suited to smooth outer conductor or spiralled outer conductor coaxial cables.
The present invention also includes method for connecting coaxial cables which remedies these inconveniences and due to which the deformation of the outer conductor of the cable is always identically the same.